Journal article
Conservation of L and 3C proteinase activities across distantly related aphthoviruses
Department of Microbiology and Immunology and the Co-operative Research Centre for Vaccine Technology, The University of Melbourne, Victoria 3010, Australia1.1
BBSRC Institute for Animal Health, Pirbright, Woking, Surrey GU24 0NF, UK2.2
The Walter and Eliza Hall Institute of Medical Research, PO The Royal Melbourne Hospital, Melbourne, Victoria 3050, Australia3.3
The foot-and-mouth disease virus (FMDV) leader (L) proteinase is an important virulence determinant in FMDV infections. It possesses two distinct catalytic activities: (i) C-terminal processing at the L/VP4 junction; and (ii) induction of the cleavage of translation initiation factor eIF4G, an event that inhibits cap-dependent translation in infected cells.
The only other member of the Aphthovirus genus, equine rhinitis A virus (ERAV), also encodes an L protein, but this shares only 32% amino acid identity with its FMDV counterpart. Another more distantly related picornavirus, equine rhinitis B virus (ERBV), which is not classified as an aphthovirus, also encodes an L protein.
Using in vitro transcription and translation analysis, we have shown that both ERAV and ERBV L proteins have C-terminal processing activity. Furthermore, expression of ERAV L, but not ERBV L, in BHK-21 cells resulted in the efficient inhibition of cap-dependent translation in these cells. We have shown that the ERAV and FMDV L proteinases induce cleavage of eIF4GI at very similar or identical positions.
Interestingly, ERAV 3C also induces eIF4GI cleavage and again produces distinct products that co-migrate with those induced by FMDV 3C. The ERBV L proteinase does not induce eIF4GI cleavage, consistent with its inability to shut down cap-dependent translation. We have also shown that another unique feature of FMDV L, the stimulation of enterovirus internal ribosome entry site (IRES) activity, is also shared by the ERAV L proteinase but not by ERBV L.
The functional conservation of the divergent ERAV and FMDV proteinases indicates the likelihood of a similar and important role for these enzymes in the pathogenesis of infections caused by these distantly related aphthoviruses.
Language: | English |
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Publisher: | Microbiology Society |
Year: | 2002 |
Pages: | 3111-3121 |
ISSN: | 14652099 and 00221317 |
Types: | Journal article |
DOI: | 10.1099/0022-1317-83-12-3111 |
ORCIDs: | Belsham, Graham J |
3C Viral Proteases Amino Acid Sequence Animals Aphthovirus Cell Line Chlorocebus aethiops Conserved Sequence Cricetinae Cysteine Endopeptidases Endopeptidases Eukaryotic Initiation Factor-4G Foot-and-Mouth Disease Virus Molecular Sequence Data Protein Biosynthesis Vero Cells Viral Proteins leader proteinase, foot-and-mouth disease virus